January 6, 2026
Sibling rivalry, but make it code
Representing Hierarchies
Two ways to build digital family trees spark a messy comment war
TLDR: The post compares two ways to organize “family tree” data: a child list versus first-child/next-sibling pointers. Comments erupted, with one voice calling the “allocation-free” pitch misleading and others defending traversal speed; the debate matters because it impacts app performance, simplicity, and how developers think about memory.
Today’s hot dev debate: how to represent digital family trees. The post breaks it down to two styles: the “kids-in-a-list” model (a node keeps a list of its children) versus the “first child, next sibling” model (each node points to its first kid and its next brother). The list makes it easy to grab “child number three,” but can mean extra memory juggling. The sibling style skips those allocations and loves fast walk-throughs, especially in game scenes and 3D transforms, but it makes picking a specific child slower.
Then the comments exploded. User jeffjeffbear led the charge, calling the “allocation-free” claim marketing-speak and warning it drags in all the usual linked-list headaches. Others argued readability matters more than micro speed hacks; fans fired back that most code just walks trees, not index-picks. One meme dubbed it “Linked List Enjoyers vs Vector Supremacists,” with the dog-in-a-burning-room gif captioned “this is fine, the heap is on fire.” A few pragmatists suggested big-block allocators and memory arenas. When the author plugged Bluesky, the thread joked: “Follow me for more sibling drama.” Meanwhile, newbies begged for plain-English guidance, and veterans responded with war stories about cache misses and pointer spaghetti. Cue popcorn everywhere.
Key Points
- •Two tree representations are compared: vector-of-children vs first-child/next-sibling.
- •Vector-of-children enables efficient indexed child access but increases dynamic allocations and potential cache misses.
- •Mitigations for the vector approach include fixed-size arrays and small buffer optimization (similar to SSO).
- •First-child/next-sibling reduces allocation overhead and indirection, suiting intrusive structures but makes indexed access linear.
- •The first-child/next-sibling layout is useful when workloads emphasize traversal (e.g., 3D transform hierarchies).